A phenomenon that occurs when you're stopped in your tracks or cease to do something that you used to: popularised in today's culture by Skyrim with the famous phrase "I used to be an adventurer like you, but then I took an arrow to the knee." iterated by guards that pop up in the game. Since Skyrim's release it has found popular use around the interweb, having been parodied thousands of times in youtube videos and comments it has become a meme. The phrase can be applied to any everyday situation by "I used to .... but then I took an arrow to the knee"

"I used to post definitions on urban dictionary, but then I took an arrow to the knee"

A phrase that is fairly old but popularized into a meme via the Skyrim quote

"I used to be an adventurer like you, but then I took an arrow to the knee"

It has since found its way into youtube and message boards alike. Where a comment vaguely involving a video on youtube coupled with the phrase "but then I took an arrow to the knee" can attract hundreds of thumbs up.
It has since become more of spam then anything being put everywhere on every video regardless of relation. However it still fits on skyrim videos and is rather funny when paired correctly.

Me: -Browsing youtube-

Me: -reads comments on video about chocolate bar-

Comments: I USED TO EAT CHOCOLATE LIKE YOU BUT THEN I TOOK AN ARROW TO THE KNEE

Arrow to the knee is kind of a joke that originated from a video game called Skyrim. The line from the game is "I used to be an adventurer like you...then I took an arrow to the knee". Many people like to use the phase "...arrow to the knee" at the end of a sentence to compare themselves to what the person can do, or what they are doing.

Man 1 I used to write like you... until I took an arrow to the knee.
Man 2 What?
Man 1 An arrow to the knee.
Man 2 Sorry to hear that.